MR sensors may be used to read data recorded at high densities on magnetic media such as magnetic tape or hard disk drive platters. The trend of decreasing feature sizes of magnetoresistive sensors can make them increasingly vulnerable to voltages and currents outside of a sensor's specified safe operating voltage range. One type of voltage excursion outside of the specified safe operating voltage range may be electrostatic discharge (ESD). ESD events can cause permanent damage to thin film layers of MR sensors such as insulating barriers (dielectric layers) and resistor metallization.
In order to function properly and avoid being damaged by ESD, MR sensors may need to be protected from voltages outside their specified safe ranges of operation. A protection circuit closely coupled to the sensor may be used to shield sensitive electrical regions and structures within the sensor from damage due to ESD events, and may ensure continued reliable functioning of the sensor.